18 research outputs found
Assessment of intimate partner violence by child welfare services
The purpose of this study was to describe policy and practice with respect to the assessment of intimate partner violence in a sample of child welfare agencies located throughout the United States and to examine the relationship of contextual characteristics and assessment practices. Telephone interviews were conducted with key informants from child welfare agencies. A snowball interviewing strategy was used to identify the best informant in each agency. Almost all of the participating agencies conducted some assessment of intimate partner violence, with most reporting that the majority of screening or assessment occurred during investigation of referrals. However, only 43.1% reported that all of the families referred to the child welfare system were assessed for intimate partner violence, and 52.8% indicated they had a written policy pertaining to screening and assessment of the problem. There was little relationship between county or agency characteristics and assessment practices. Additional research is needed to determine factors that influence assessment practices and to identify strategies to support and extend efforts to identify intimate partner violence and provide appropriate services for families in the child welfare system
A novel gas divider using nonlinear laminar flow
Gas dividers are important in emissions measurement since they continuously and accurately mix two gases to create a known gas concentration that is needed in the multi-point calibration of gas analyzers. A novel gas divider was designed using nonlinear laminar flow induced from the density change along the capillary channels due to the high-pressure drop (relative to the inlet gas pressure). The minor losses from entrance and exit effects can be ignored due to the high pressure loss from Hagen-Poiseuille\u27s law relative to the minor losses. Small diameter wires inside of a tube were used to create capillary channels through which gas could flow. The gas divider, using nonlinear laminar flow, showed lower measurement uncertainty at high (90%) dilution levels than using linear laminar flow due to the higher-pressure drop at the same volumetric flow rates. Experiments showed the expected gas concentration from using the gas divider to be within 2% of the measured gas concentrations
Development of a test apparatus to determine thermal properties of rock specimens
Understanding thermal properties is necessary for the development of both shallow and deep geothermal systems. Thermal properties can also be used for understanding the development and assessing weathering in a variety of materials. An experimental apparatus has been developed to determine the thermal properties of rock samples. The apparatus consists of a ring heater, aluminum adaptor, and a stainless steel base. Three thermocouples are used to measure heat flow through the base. The rock specimen sits on top of the stainless steel base. Twelve thermocouples, arranged vertically in sets of three at the cardinal positions around the rock sample, are used to measure heat flow through the sample. The apparatus is wrapped in insulation to prevent heat loss. The top of the apparatus is open so a thermal camera can capture the temperature increase at the top of the specimen. Thermal analyses conducted using finite element modeling have verified the design of the apparatus. Two limestone specimens have been tested and experimentally derived thermal conductivities are within experimental ranges of thermal conductivities presented in the literature
An investigation of the combustion process of a heavy-duty dual fuel engine supplemented with natural gas or hydrogen
This paper compares the effects of the addition of hydrogen (H2) or natural gas (NG) on the combustion of a heavy-duty diesel engine converted to operate under gaseous fuel-diesel dual fuel combustion mode. The parameters examined include the start of combustion (SOC), heat release process, peak heat release rate (PHRR), and combustion duration. Significant positive effects on the combustion process were only observed with the addition of a relatively large amount of H2 or NG. When operated at low load, the addition of a large amount of H2 or NG reduced the heat release rate (HRR) of the premixed combustion. By comparison, the addition of a relatively large amount of H2 or NG at high load significantly increased the PHRR of the diffusion combustion. The addition of H2 has more significant impact on the PHRR than NG. The addition of NG retarded the SOC while the impact of the addition of H2 on SOC was relatively mild. The significant variation in HRR and its phasing make it necessary to further optimize the combustion of a dual fuel engine. The impact of the addition of gaseous fuel on the brake thermal efficiency was also examined and discussed. The increased thermal efficiency was only observed with the addition of relatively large amount of H2 or NG at medium to high load. The improved thermal efficiency was due to the decrease in combustion duration and the shifting of the combustion phasing toward the optimal one. The decreased thermal efficiency observed at low load was due to the low combustion efficiency of the gaseous fuel supplemented
Design and Testing of an Independently Controlled Urea SCR Retrofit System for the Reduction of NO x
Thermal Conductivity Measurements of Weathered Limestone
Thermal properties of geological materials are required for analysis and design of energy geostructures. In Florida the weathered limestone bedrock, which has highly variable engineering properties, can be found near the ground surface and its thermal properties will need to be incorporated into the design of such systems. Thermal conductivity values for split tension sized specimens were determined using a specially designed thermal apparatus. The apparatus is capable of determining four thermal conductivity values for each specimen, which provided a measure of variability of the measurements. Thermal conductivities ranged between 2.65 and 3.75 W/m-K with specimen measurement standard deviations and coefficient of variations as high as 0.415 W/m-K and 11.1%, respectively. The variability of the results can be attributed to both dissolution, which would decrease thermal conductivity, and dolotomitization, which would increase thermal conductivity. Thermal conductivity values are in the lower range of values reported in the literature
Thermal Conductivity Measurements of Weathered Limestone
Thermal properties of geological materials are required for analysis and design of energy geostructures. In Florida the weathered limestone bedrock, which has highly variable engineering properties, can be found near the ground surface and its thermal properties will need to be incorporated into the design of such systems. Thermal conductivity values for split tension sized specimens were determined using a specially designed thermal apparatus. The apparatus is capable of determining four thermal conductivity values for each specimen, which provided a measure of variability of the measurements. Thermal conductivities ranged between 2.65 and 3.75 W/m-K with specimen measurement standard deviations and coefficient of variations as high as 0.415 W/m-K and 11.1%, respectively. The variability of the results can be attributed to both dissolution, which would decrease thermal conductivity, and dolotomitization, which would increase thermal conductivity. Thermal conductivity values are in the lower range of values reported in the literature
Effect of mechanical assistance of the systemic ventricle in single ventricle circulation with cavopulmonary connection
BackgroundPrevious attempts to support single ventricle circulation mechanically have suggested that a custom-built assist device is needed to push, rather than pull, through the pulmonary circulation. We hypothesized that using a conventional ventricular assist device, with or without conversion of a total cavopulmonary connection to a bidirectional Glenn cavopulmonary connection, would allow assistance by pulling blood through the circuit and improve the cardiac index (CI).MethodsCavopulmonary connections were established in each of 5 Yorkshire pigs (25 kg) using ePTFE conduits in a Y configuration with appropriate clamping of the limbs of the Y to achieve a total cavopulmonary Fontan connection (TCPC), superior vena cava cavopulmonary connection (SVC Glenn), and inferior vena cava cavopulmonary connection (IVC Glenn). A common atrium had been established previously by balloon septostomy. Mechanical circulatory assistance of the single systemic ventricle was achieved using a centrifugal pump with common atrial inflow and proximal ascending aortic outflow. The CI was calculated using an ultrasonic flow meter placed on the distal ascending aorta and compared between the assisted and nonassisted circulation for 3 conditions: TCPC, SVC Glenn, and IVC Glenn. The mean pulmonary artery pressure, common atrial pressure, arterial oxygen saturation, partial pressure of arterial oxygen, and oxygen delivery were calculated.ResultsThe unassisted SVC Glenn CI tended to be greater than the TCPC or IVC Glenn CI. Significant augmentation of total CI was achieved with mechanical assistance for SVC Glenn (109% ± 24%, P = .04) and TCPC (130% ± 109%, P = .01). The assisted CI achieved at least a mean baseline biventricular CI for all 3 support modes. Oxygen delivery was greatest for assisted SVC Glenn (1786 ± 1307 mL/L/min) and lowest for TCPC (1146 ± 386 mL/L/min), with a trend toward lower common atrial and pulmonary artery pressures for SVC Glenn.ConclusionsSVC bidirectional Glenn circulation might allow optimal augmentation of the CI and oxygen delivery in a failing single ventricle using a conventional pediatric ventricular assist device. The results from our model also suggest that the Fontan circulation itself can be supported with systemic ventricular assistance of the single ventricle